Apparatus for performing an electrosurgical procedure

ABSTRACT

A forceps includes a housing having a shaft. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other jaw member from a clamping position to an open position. A resilient member operably couples to the first and second jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 16/435,632, filed on Jun. 10, 2019, which is a continuation of U.S. patent application Ser. No. 15/194,171, filed on Jun. 27, 2016, now U.S. Pat. No. 10,314,646, which is a continuation of U.S. patent application Ser. No. 14/035,423, filed on Sep. 24, 2013, now U.S. Pat. No. 9,375,227, which is a divisional of U.S. patent application Ser. No. 12/792,330, filed Jun. 2, 2010, now U.S. Pat. No. 8,540,749.

INTRODUCTION

The present disclosure relates to an apparatus for performing an electrosurgical procedure. More particularly, the present disclosure relates to an electrosurgical apparatus including an end effector assembly having a pair of jaw members that provide a mechanical advantage at the end effector.

BACKGROUND

Electrosurgical instruments, e.g., electrosurgical forceps (open or closed type), are well known in the medical arts and typically include a housing, a handle assembly, a shaft and an end effector assembly attached to a distal end of the shaft. The end effector includes jaw members configured to manipulate tissue (e.g., grasp and seal tissue). Typically, the electrosurgical forceps utilizes both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, seal, cut, desiccate, and/or fulgurate tissue. Typically, one or more driving mechanisms, e.g., a drive assembly including a drive rod, is utilized to cooperate with one or more components operatively associated with the end effector to impart movement to one or both of the jaw members.

In certain instances, to facilitate moving the jaw members from an open position for grasping tissue to a closed position for clamping tissue (or vice versa) such that a consistent, uniform tissue effect (e.g., tissue seal) is achieved, one or more types of suitable devices may be operably associated with the electrosurgical forceps. For example, in some instances, one or more types of springs, e.g., a compression spring, may operably couple to the handle assembly associated with the electrosurgical forceps. In this instance, the spring is typically operatively associated with the drive assembly to facilitate actuation of a movable handle associated with the handle assembly to ensure that a specific closure force between the jaw members is maintained within one or more suitable working ranges.

In certain instances, the shaft may bend or deform during the course of an electrosurgical procedure. For example, under certain circumstances, a clinician may intentionally bend or articulate the shaft to gain desired mechanical advantage at the surgical site. Or, under certain circumstances, the surgical environment may cause unintentional or unwanted bending or flexing of the shaft, such as, for example, in the instance where the shaft is a component of a catheter-based electrosurgical forceps. More particularly, shafts associated with catheter-based electrosurgical forceps are typically designed to function with relatively small jaw members, e.g., jaw members that are configured to pass through openings that are 3 mm or less in diameter. Accordingly, the shaft and operative components associated therewith, e.g., a drive rod, are proportioned appropriately. That is, the shaft and drive rod are relatively small.

As can be appreciated, when the shaft is bent or deformed (either intentionally or unintentionally) the frictional losses associated with drive rod translating through the shaft are transferred to the spring in the housing, which, in turn, may diminish, impede and/or prevent effective transfer of the desired closure force that is needed at the jaw members. Moreover, the frictional losses may also lessen the operative life of the spring, which, in turn, ultimately lessens the operative life of the electrosurgical instrument.

SUMMARY

The present disclosure provides an endoscopic forceps. The endoscopic forceps includes a housing having a shaft that extends therefrom having a longitudinal axis defined therethrough. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other jaw member from an open position to a clamping position. One of the first and second jaw members includes one or more cam slots defined therein and is configured to receive a cam member that upon movement thereof rotates the jaw members from the clamping position to the open position. A resilient member is operably coupled to one or both of the jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween.

The present disclosure provides an endoscopic forceps. The endoscopic forceps includes a housing having a shaft that extends therefrom having a longitudinal axis defined therethrough. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. The first and second jaw members each having a respective detent operably disposed at a proximal end thereof. The first and second jaw members movable relative to one another from a clamping position wherein the first and second jaw members cooperate to grasp tissue therebetween to an open position wherein the first and second jaw members are disposed in spaced relation relative to one another. A cam assembly is movable along the longitudinal axis and includes one or more cam slots defined therein. The one or more cam slots are configured to receive the detent associated with the respective first and second jaw members. A resilient member operably couples to the cam assembly and is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween.

The present disclosure provides an endoscopic forceps. The endoscopic forceps includes a housing having a shaft that extends therefrom having a longitudinal axis defined therethrough. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other jaw member that is stationary from an open position to a clamping position. A support member is operably disposed at a distal end of the shaft adjacent the end effector. A resilient member in mechanical communication with the support member operably couples to the first and second jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween.

In embodiments, a plurality of non-conductive stop members is disposed on an inner facing surface of one or both of the first and second jaw members. The stop members are configured to maintain a uniform distance between the first and second jaw members along the length thereof during tissue sealing.

The present disclosure also provides a method for performing a laparoscopic surgical procedure. The method includes providing an endoscopic instrument that includes an end effector assembly including a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other from a clamping position to an open position. The movable jaw member includes one or more cam slots defined therein that is configured to receive a cam member. A resilient member is operably coupled to one or both of the first and second jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween. A step of the method includes biasing the first and second jaw members in the clamping position with the resilient member for positioning the end effector adjacent to tissue. Moving the movable jaw member to the open position is a step of the method. Positioning tissue between the first and second jaw members is another step of the method. And, moving the movable jaw member to the clamping position is still yet another step of the method.

BRIEF DESCRIPTION OF THE DRAWING

Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein:

FIG. 1A is a side, perspective view of an endoscopic bipolar forceps showing an end effector assembly including jaw members in a closed configuration according to an embodiment of the present disclosure;

FIG. 1B is a side, perspective view of the endoscopic bipolar forceps depicted in FIG. 1A illustrating internal components of a handle assembly associated with the endoscopic bipolar forceps;

FIG. 2 is a schematic view of the jaw members depicted in FIGS. 1A and 1B operably coupled to a jaw housing associated with each of the jaw members;

FIGS. 3A and 3B are schematic views of jaw members operably coupled to a distal end of the endoscopic forceps depicted in FIGS. 1A and 1B according to another embodiment of the present disclosure;

FIGS. 4A and 4B are schematic views of jaw members operably coupled to a distal end of the endoscopic forceps depicted in FIGS. 1A and 1B according to yet another embodiment of the present disclosure; and

FIG. 5 is a side, perspective view of an endoscopic bipolar forceps showing an end effector assembly including jaw members in an open configuration according to still another embodiment of the present disclosure.

DETAILED DESCRIPTION

Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.

With reference to FIGS. 1A and 1B, an illustrative embodiment of an electrosurgical apparatus, e.g., a bipolar forceps 10 (forceps 10) is shown. Forceps 10 is operatively and selectively coupled to a suitable power source, such as, for example, an electrosurgical generator (not shown) for performing an electrosurgical procedure. As noted above, an electrosurgical procedure may include sealing, cutting, cauterizing coagulating, desiccating, and fulgurating tissue all of which may employ RF energy. The generator may be configured for monopolar and/or bipolar modes of operation. The generator may include or is in operative communication with a system (not shown) that may include one or more processors in operative communication with one or more control modules that are executable on the processor. The control module (not explicitly shown) may be configured to instruct one or more modules to transmit electrosurgical energy, which may be in the form of a wave or signal/pulse, via one or more cables (e.g., a cable 23) to the forceps 10.

Forceps 10 is shown configured for use with various electrosurgical procedures and generally includes a housing 20, electrosurgical cable 23 that connects the forceps 10 to a source of electrosurgical energy (e.g., the electrosurgical generator), a handle assembly 30, a rotating assembly 80, a trigger assembly 70, a drive assembly 130 (see FIG. 1B), and an end effector assembly 100 that operatively connects to a drive element 150 of the drive assembly 130. End effector assembly 100 includes opposing jaw members 110 and 120 (FIGS. 1A and 1B) that mutually cooperate to grasp, seal and, in some cases, divide large tubular vessels and large vascular tissues. The drive assembly 130 is in operative communication with handle assembly 30 for imparting movement of one or both of a pair of jaw members 110, 120 of end effector assembly 100. Conventional drive assemblies typically utilize one or more types of springs, e.g., a compression spring, to facilitate closing the jaw members 110 and 120. For illustrative purposes, a compression spring 131 (see FIG. 1B) is shown separated from the housing 20.

With continued reference to FIGS. 1A and 1B, forceps 10 includes a shaft 12 that has a distal end 14 configured to mechanically engage the end effector assembly 100 and a proximal end 16 that mechanically engages the housing 20. In the drawings and in the descriptions that follow, the term “proximal,” as is traditional, will refer to the end of the forceps 10 which is closer to the user, while the term “distal” will refer to the end that is farther from the user.

Handle assembly 30 includes a fixed handle 50 and a movable handle 40. Fixed handle 50 is integrally associated with housing 20 and handle 40 is movable relative to fixed handle 50. Movable handle 40 of handle assembly 30 is ultimately connected to the drive assembly 130, which together mechanically cooperate to impart movement of one or both of the jaw members 110 and 120 to move from a clamping or closed position (FIG. 1A), wherein the jaw members 110 and 120 cooperate to grasp tissue therebetween, to an open position (FIG. 1B), wherein the jaw members 110 and 120 are disposed in spaced relation relative to one another.

Jaw members 110, 120 are operatively and pivotably coupled to each other and located adjacent the distal end 14 of shaft 12. Respective electrically conductive seal plates 118 and 128 are operably supported on and secured to respective jaw housings 117 and 127 of respective the jaw members 110 and 120, described in greater detail below. For the purposes herein, jaw members 110 and 120 include jaw housings 117 and 127 that are configured to support sealing plates 118 and 128, respectively.

For a more detailed description of the forceps 10 including handle assembly 30 including movable handle 40, rotating assembly 80, trigger assembly 70, drive assembly 130, jaw members 110 and 120 (including coupling methods utilized to pivotably couple the jaw members 110 and 120 to each other) and electrosurgical cable 23 (including line-feed configurations and/or connections), reference is made to commonly owned U.S. Pat. No. 7,766,910 filed on Nov. 9, 2006.

Turning now to FIG. 2, one embodiment of jaw housings 117 and 127 is shown. It should be noted that in accordance with the present disclosure one or both of the jaw housings 117 and 127 may include a proximal end that is configured to support one or more cam slots 202 and resilient members 204 to facilitate closing in of the jaw members 110 and 120. Jaw members 110 and 120 are substantially identical to each other, and, in view thereof, and so as not to obscure the present disclosure with redundant information, the operative components associated with the jaw housing 117 are described in further detail with respect to jaw member 110, and only those features distinct to jaw member 120 and jaw housing 127 will be described hereinafter.

With continued reference to FIG. 2, jaw member 110, jaw housing 117, and operative components associated therewith may be formed from any suitable material, including but not limited to metal, metal alloys, plastic, plastic composites, etc. In the embodiment illustrated in FIG. 2, jaw member 110 is formed from metal.

A distal end 117 a of the jaw housing 117 of jaw member 110 is configured to securely engage the electrically conductive seal plate 118. A portion of a proximal end 117 b of the jaw member 110 is operably secured to the distal end 14 of the shaft 12. More particularly, a portion of proximal end 117 b operably couples to the distal end 14 and is in operative communication with the drive element 150 of the drive assembly 130 such that movement of the drive element 150 causes one or both of the jaw members 110 and 120 to move from the closed or clamping position to the open position and vice versa. For example, in one particular embodiment, when the drive element 150 is “pulled,” i.e., moved or translated proximally, one or both of the jaw members 110 and 120 is/are caused to move away from the other. Alternatively, and if desired, the drive assembly 130 including the drive element 150 may be configured such that when the drive element 150 is “pushed,” i.e., moved or translated distally, one or both of the jaw members 110 and 120 are caused to move away from each other. In certain instances, it may prove useful to have a drive element 150 that is flexible. More particularly, where the drive element 150 is operatively associated with an endoluminal instrument the drive element 150 may be substantially flexible to accommodate bends typically associated with that type of instrument when the bipolar forceps 10 is remotely actuatable relative to the patient.

In the illustrated embodiment, proximal end 117 b of the jaw housing 110 includes a generally elongated configuration that may be rectangular, circumferential or combination thereof in shape.

Proximal end 117 b of the jaw member 110 includes one or more cam slots 202 defined therein that support one or more cam members 205 (see FIG. 2). More particularly, cam slot 202 is of suitable proportion and configured to receive cam member 205 and is operably formed and/or positioned at the proximal end 117 b of the jaw housing 117. Cam slot 202 includes a generally oblique configuration with respect to a longitudinal axis “B-B” that is parallel to a longitudinal axis “A-A” defined through the shaft 12, see FIGS. 1A and 2. Cam slot 202 may extend at an angle that ranges from about 5° to about 30° with respect to the longitudinal axis “B-B.” In the embodiment illustrated FIG. 2, cam slot 202 extends at an angle that is approximately equal to 45° with respect to the longitudinal axis “B-B.” The angle of the cam slot 202 may be selectively varied depending upon a particular instrument, use or manufacturing preference.

An opening 208 is defined in and extends through the jaw housing 117 b and is configured to receive a spring pin 211. Opening 208 is shown engaged with spring pin 211 and as such is not explicitly visible. In the embodiment illustrated in FIG. 2, a portion of the spring pin 211 is dimensioned to securely engage the resilient member 204.

One or more types of resilient members 204 may be operably associated with the housing 117 and includes, for example, a torsion spring that is utilized to generate a closure force on the jaw members 110 and 120 when the jaw members 110 and 120 are in a closed or clamped position. The resilient member 204 cooperates with the drive assembly 130 to provide the necessary closure force on the jaw members 110 and 120 for sealing tissue, e.g., in the range of about 3 kg/cm² to about 16 kg/cm².

Resilient member 204 operably engages jaw housings 117 and 127 and is biased in a closed orientation. More particularly, a proximal end 212 of suitable proportion and having a generally circumferential configuration is dimensioned to securely couple to the spring pin 211. Two generally elongated fingers 214 and 216 extend from proximal end 212 adjacent the proximal ends of the jaw members, e.g., proximal end 117 b of jaw member 110 and a proximal end (not explicitly shown) of the jaw member 120, and fixedly couple to a respective distal end of the jaw member, e.g., distal end 117 a of jaw member 117 and a distal end 127 a of the jaw member 120. In the embodiment illustrated in FIG. 2, the resilient member 204 biases the jaw members 110 and 120 toward each other to a closed position such that a consistent uniform seal is effected to tissue. More particularly, the configuration of the resilient member 204 is designed such that each the elongated fingers 214 and 216 are operably disposed adjacent a respective imaginary center-line “CL” that extends through each of the jaw members 110 and 120, see FIG. 2. In this instance, the force from each of the elongated fingers 214 and 216 is evenly distributed to and throughout a respective jaw member.

One or more types of lubricious materials (not shown), e.g., PTFE, may coat cam slot 202 or an inner peripheral surface thereof. Coating the cam slot 202 with the lubricious material facilitates movement of the cam member 205 within the cam slot 202 when the drive element 150 is translated proximally (or distally depending on a particular configuration).

In an assembled configuration each of the jaw members 110 and 120 are positioned in side-by-side relation. Cam member 205 is operably disposed within cam slot 202 associated with jaw member 110 and a corresponding cam slot (not explicitly shown) associated with jaw member 120. Spring pin 211 is positioned within the opening associated with jaw member 110 and a corresponding opening (not explicitly shown) associated with jaw member 120. As noted above, the spring pin 211 provides a point of pivot for each of the jaw members 110 and 120. Once assembled, the jaw members 110 and 120 may be pivotably supported at the distal end 14 of the shaft 12 by known methods, such as, for example, by the method described in commonly-owned U.S. Patent Publication No. 2007/0260242 filed on Jul. 11, 2007.

In use, initially jaw members 110 and 120 are biased in a closed position under the closure and/or sealing force provided by the resilient member 204. Proximal movement of movable handle 40 causes the drive element 150 to move proximally. Proximal movement of the drive element 150 causes cam member 205 positioned within the cam slot 202 to move proximally against the bias of the resilient member 204, which, in turn, causes both of the jaw members 110 and 120 to move relative to one another, such that tissue is positioned between the jaw members 110 and 120. Once tissue is positioned between the jaw members 110 and 120 the movable handle 40 is released, which, in turn, causes the jaw members 110 and 120 to move toward one another under the biasing force of the resilient member 204 which generates a sealing or closure force on the tissue disposed between the jaw members 110 and 120. The resilient member 204 provides an additional mechanical advantage at the jaw members 110 and 120 and reduces the frictional losses that are typically associated with conventional forceps when a drive rod is translated within a shaft to make the necessary closure force to seal tissue, e.g., the closure force is offloaded and/or diminished by the resilient member 204.

With reference to FIGS. 3A and 3B, another embodiment of an end effector 300 that is configured for use with the forceps 10 is illustrated. End effector 300 is substantially identical to end effector 100, and, in view thereof, and so as not to obscure the present disclosure with redundant information, and only those features distinct to end effector 300 will be described hereinafter.

End effector 300 includes jaw members 310 and 320. As described above with respect to jaw members 110 and 120, jaw members 310 and 320 are pivotably coupled to each other via a spring pin or pivot pin 311. More particularly, pivot pin 311 operably couples the jaw members 310 and 320 about a medial portion of a respective jaw housing 317 and 327 (FIG. 3A). Pivot pin 311 maintains the jaw members 310 and 320 in a substantially fixed position with respect to the longitudinal axis “A-A” when the jaw members 310 and 320 are pivoting or rotating about the pivot pin 311. That is, the jaw members 310 and 320 do not translate along the longitudinal axis “A-A” when movable handle 40 is moved.

A respective detent 313 and 323 is operably disposed at a respective proximal end 317 b and 327 b of the jaw members 310 and 320, respectively. In the embodiment illustrated in FIGS. 3A and 3B, the detents 313 and 323 are configured to rotate the respective jaw members 310 and 320 from an open position (FIG. 3A) to a closed or clamping position (FIG. 3B) when the movable handle 40 is moved proximally. Detents 313 and 323 are proportioned to movably couple to a cam assembly 330.

Cam assembly 330 translates or moves along the longitudinal axis “A-A” when the movable handle 40 is moved proximally and/or distally. To this end, cam assembly 330 is suitably shaped and proportioned to movably reside within the shaft 12 adjacent the distal end 14. For illustrative purposes, cam assembly 330 is shown elongated with a generally rectangular shape. One or more cam slots 332 are operably disposed on or defined in the cam assembly 330. In the embodiment illustrated in FIGS. 3A and 3B, two intersecting cam slots 332 a and 332 b are defined in the cam assembly 330. The cam slots 332 a and 332 b are proportioned to receive a respective detent 313 and 323 such that the detents 313 and 323 are movable along a length of the respective cam slots 332 a and 332 b.

Each of the cam slots 332 a and 332 b includes a respective distal end 334 and 336. The distal ends 334 and 336 are configured to function as latches. More particularly, the distal ends 334 and 336 maintain the respective detents 313 and 323 in a substantially fixed position after the movable handle 40 is moved a predetermined distance proximally and the jaw members 310 and 320 are in the clamping position.

One or more suitable unlatching devices or configurations may be utilized to unlatch the detents 313 and 323 from the respective distal ends 334 and 336. For example, and in one particular embodiment, one or more detents 335 may be operably disposed along an internal surface of the shaft 12. In this instance, the detent 335 may be configured to contact a portion, e.g., a bottom surface 331, of the cam assembly 330 when the movable handle 40 is moved through an “unlatching” stroke, see FIGS. 3A and 3B. Accordingly, when movable handle 40 is moved through the “unlatching” stroke, the detent 335 contacts the bottom surface 331 of the cam assembly 330, which, in turn, unlatches the detents 313 and 323 from the respective distal ends 334 and 336. Other latching and unlatching devices and/or configurations may be utilized to latch and unlatch the detents 313 and 323 from the respective distal ends 334 and 336.

One or more types of resilient members 304 operably couple to the drive element 150 and to the cam assembly 330. Resilient member 304 may be any suitable resilient member, e.g., a compression spring. A distal end of the drive element 150 operably couples to a proximal end of the resilient member 304 and proximal end of the cam assembly 330 operably couples to a distal end of the resilient member 304. The resilient member 304 operably couples to the distal end of the drive element 150 and proximal end of the cam assembly 330 via any suitable coupling methods. As described above with resilient member 204, resilient member 304 cooperates with the drive assembly 130 to provide the necessary closure force on the jaw members 310 and 320 for sealing tissue, e.g., in the range of about 3 kg/cm² to about 16 kg/cm².

In use, initially jaw members 310 and 320 are biased in an open position (FIG. 3A). Tissue is positioned between the jaw members 310 and 320. Thereafter, the movable handle 40 is moved proximally causing the drive element 150 to move proximally. Proximal movement of the drive element 150 moves the resilient member 304 proximally, which, in turn, moves the cam assembly 330 proximally. Proximal movement of the cam assembly 330 causes the detents 313 and 323 to move within the respective cam slots 332 a and 332 b and to the respective distal ends 334 and 336 until the detents 313 and 323 are latched into a closed or clamping position (FIG. 3B). In the latched position, the requisite sealing or closure force is present on the tissue disposed between the jaw members 310 and 320. Thereafter, electrosurgical energy is transmitted to seal surfaces 318 and 328 operably associated with respective jaw members 310 and 320 such that a desired tissue effect, e.g., a tissues seal, may be achieved on the tissue disposed between the jaw members 310 and 320. To open the jaw members 310 and 320, the moveable handle 40 is moved through an “unlatching” stroke that unlatches or releases the detents 313 and 323 from the respective distal ends 334 and 336 such that the jaw members 310 and 320 return to the initial open position.

With reference to FIGS. 4A and 4B, an end effector 400 that is configured for use with the forceps 10 is illustrated. End effector 400 is substantially identical to end effectors 100 and 300, and, in view thereof, and so as not to obscure the present disclosure with redundant information, only those features distinct to end effector 400 will be described hereinafter.

End effector 400 includes jaw members 410 and 420. In the embodiment illustrated in FIGS. 4A and 4B, one of the jaw members, e.g., jaw members 420, is movable, and one of the jaw members, e.g., jaw member 410, is stationary. This configuration of jaw members 420 and 410 may be reversed to accommodate various surgical procedures. Jaw members 410 and 420 are pivotably coupled to one another via a pivot pin 411.

A support structure or member 430 is operably disposed along an internal frame of the shaft 12 adjacent the distal end 14. More particularly, the support structure 430 is operably coupled to a top portion of the internal frame of the shaft 12. Support structure 430 is configured to mechanically communicate with a resilient member 404. More particularly, the support structure 430 provides a substantially rigid surface that is configured to compress the resilient member 404 when the resilient member 404 is moved proximally and the movable jaw member 420 is moved to the open position. To this end, support structure 430 may have any suitable shape. In the embodiment illustrated in FIGS. 4A and 4B, support structure 430 includes a generally circumferential configuration having an aperture 406 of suitable proportion defined therethrough. Aperture 406 is includes a diameter that is sized to receive the drive element 150 (or portion thereof) that includes a distal end that operably couples to a proximal end 427 b of the movable jaw member 420. More particularly, the diameter of the aperture 406 is such that the drive element 150 is movable through the aperture 406 when the movable handle 40 is moved proximally and/or distally. Additionally, the aperture 406 is proportioned such that the resilient member 404 is prevented from translating therethrough when the movable handle 40 is moved proximally and/or distally.

In the embodiment illustrated in FIGS. 4A and 4B, the support structure 430 is configured to maintain the drive element 150 in a substantially fixed off-set orientation above the pivot pin 411, see FIG. 4A, for example. Having the support structure 430 configured in such a manner facilitates moving the jaw member 420 about the pivot pin 411.

Resilient member 404 is operably disposed between the support structure 430 and the proximal end 427 b of the jaw housing 427. In an uncompressed state, resilient member 404 cooperates with the support structure 430 to provide the necessary closure force on the jaw members 410 and 420 for sealing tissue, e.g., in the range of about 3 kg/cm² to about 16 kg/cm². To this end, the resilient member 404 may be any suitable resilient spring, e.g., a compression spring 404, including, but not limited to those previously described herein. The compression spring 404 is proportioned such that the drive element 150 is positionable therethrough, FIG. 4A.

In use, initially jaw members 410 and 420 are biased in a closed position under the closure and/or sealing force provided by the compression spring 404 (FIG. 4B). Proximal movement of movable handle 40 causes the drive element 150 to move proximally. Proximal movement of the drive element 150 causes the moveable jaw member, e.g., jaw member 420, to move relative to the stationary jaw member, e.g., jaw member 410, such that tissue is positioned between the jaw members 410 and 420. Once tissue is positioned between the jaw members 410 and 420 the movable handle 40 is released, which, in turn, causes the jaw member 420 to move toward jaw member 410 under the biasing force of the compression spring 404 which generates a sealing or closure force on the tissue disposed between the jaw members 410 and 420. The compression spring 404 provides an additional mechanical advantage at the jaw members 410 and 420 and reduces the frictional losses that are typically associated with conventional forceps when a drive rod is translated within a shaft to make the necessary closure force to seal tissue, e.g., the closure force is offloaded and/or diminished by the compression spring 404.

From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, other resilient members, e.g., leaf springs, compressed gas, resilient bladder, spring washers and bellows, may be operably associated with any of the aforementioned configurations of utilized to generate a closure or sealing force at the jaw members. Moreover, the resilient members 204, 304 and 404 may work in combination with one or more springs located with the shaft 12 or housing 20 that are operatively associated with the drive assembly 130 to generate the necessary forces associated with tissue sealing.

As best seen in FIG. 5, in order to achieve a desired spacing between the electrically conductive surfaces of the respective jaw members, e.g., jaw members 110 and 120, (i.e., gap distance) and apply a desired force to seal the tissue, one or both of the jaw member 110 and/or 120 may include one or more stop members 350 that limit the movement of the two opposing jaw members 110 and 120 relative to one another. The stop member 350 may be disposed on an inner facing surface of one or both of the jaw members 110 and 120. More particularly, stop member 350 extends from a seal surface 118 a of seal plate 118 a predetermined distance according to the specific material properties (e.g., compressive strength, thermal expansion, etc.) to yield a consistent and accurate gap distance during sealing. In the illustrated embodiment, the stop members 350 extend from the seal surfaces 118 a and 128 a a distance that ranges from about 0.001 inches to about 0.006 inches. The gap distance between opposing sealing surfaces 118 a and 128 a during sealing may range from about 0.001 inches to about 0.006 inches and, preferably, between about 0.002 and about 0.003 inches. The configuration of a seal surface 118 a with stop members 350 facilitates in maintaining a uniform distance between the jaw members 110 and 120 along the length thereof during tissue sealing.

For a more detailed description of the stop members 350 and operative components associated therewith, reference is made to commonly-owned U.S. Pat. No. 8,241,284.

While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 

1. (canceled)
 2. An electrosurgical vessel sealing instrument, comprising: a housing; a shaft extending from the housing; an end effector assembly coupled to a distal end of the shaft and including a pair of first and second jaw members configured to deliver electrosurgical energy to tissue; a cam slot defined in each of the first and second jaw members; a pair of cam members disposed within the cam slots defined by the respective first and second jaw members, the pair of cam members configured to move along a longitudinal axis defined by the shaft; a drive rod configured to move within the shaft along the longitudinal axis to move the pair of cam members within the cam slots defined by the respective first and second jaw members, thereby moving at least one of the first or second jaw members relative to the other jaw member; and a resilient member extending through the shaft and operably coupled to the drive rod and the pair of cam members, the resilient member configured to cooperate with the drive rod to cause the first and second jaw members to provide a closure force on tissue disposed between the jaw members upon proximal movement of the drive rod along the longitudinal axis.
 3. The electrosurgical vessel sealing instrument according to claim 2, wherein at least one of the first or second jaw members includes a plurality of non-conductive stop members configured to maintain a distance between the first and second jaw members.
 4. The electrosurgical vessel sealing instrument according to claim 3, wherein the plurality of non-conductive stop members maintains a distance between the first and second jaw members in the range of about 0.001 inches to about 0.006 inches.
 5. The electrosurgical vessel sealing instrument according to claim 2, wherein at least one of the first jaw member or the second jaw member is pivotable about a pivot pin.
 6. An electrosurgical vessel sealing instrument, comprising: a housing; a shaft extending from the housing; an end effector assembly coupled to a distal end of the shaft and including a first jaw member and a second jaw member, at least one of the first or second jaw members movable relative to the other jaw member; a circumferential support structure disposed within the shaft and defining an aperture therethrough; a drive rod operably coupled to at least one of the first or second jaw members and configured to translate within the shaft along the longitudinal axis and through the aperture to move at least one of the first or second jaw members relative to the other jaw member; and a resilient member extending through the shaft between the circumferential support structure and the end effector assembly.
 7. The electrosurgical vessel sealing instrument according to claim 6, wherein at least one of the first or second jaw members includes a plurality of non-conductive stop members configured to maintain a distance between the first and second jaw members.
 8. The electrosurgical vessel sealing instrument according to claim 7, wherein the plurality of non-conductive stop members maintains a distance between the first and second jaw members in the range of about 0.001 inches to about 0.006 inches.
 9. The electrosurgical vessel sealing instrument according to claim 6, wherein at least one of the first jaw member or second jaw member is pivotable about a pivot pin.
 10. The electrosurgical vessel sealing instrument according to claim 6, further comprising: a cam slot defined in each of the first and second jaw members; and a pair of cam members disposed within the cam slots defined by the respective first and second jaw members, the pair of cam members configured to move along a longitudinal axis defined by the shaft, wherein translation of the drive rod along the longitudinal axis moves the pair of cam members within the cam slots defined by the respective first and second jaw members.
 11. The electrosurgical vessel sealing instrument according to claim 10, wherein the resilient member is operably coupled to the drive rod and the pair of cam members, the resilient member configured to cooperate with the drive rod to cause the first and second jaw members to provide a closure force on tissue disposed between the jaw members upon proximal movement of the drive rod along the longitudinal axis. 